The invention concerns a hydrostatic bearing device and in particular, to a seal which is tapered and in contact with a facing sliding surface of another machine area with an extremely small contact area.
In a generally known hydrostatic bearing device according to the description of the patent claim 1 (U.S. Pat. No. 4,753,311), the fluid chamber is constantly topped off through a supply and the leakage quantity is carried off outside of a seal enclosing the fluid space. The existing solution allows only comparatively low feed velocities. If the feed velocities are higher, the large seal surface facing an opposing sliding surface develops a hydrodynamic gap and causes high leakage volume. The consequence of the high leakage volumes is that the existing bearing device has to be constantly fed with hydraulic fluid from a pressure source, usually by means of a high-pressure pump. It is therefore necessary to feed each fluid space of every pressure chamber of the possible several through a hydraulically separate supply line. Collecting the hydraulic fluid flowing out of the fluid space is also expensive.
The invention overcomes these difficulties by providing a hydrostatic bearing device with a simple construction, cost-effective manufacture and lower operating costs and which does not have the above-mentioned disadvantages of the already known hydrostatic bearing devices.
More particularly, the present invention provides a seal which is tapered and therefore is in contact with the facing sliding surface of the other machine area with an extremely small contact area, which is contoured similar to the cut. The tapering contour shape allows considerably higher feed velocities than the existing solutions. It also reduces the leakage quantity between seal and the sliding surface to such an extent that it is possible to dispense with the constant hydraulic fluid supply so indispensable with the state of the art technology. It is enough to provide only a pressure reservoir, absent in the current state of the art, in order to maintain pressure in the fluid space.
The design of the seal according to the present invention makes it possible to lengthen the interval for topping off the pressure chamber to the point that the topping off process has no adverse effect on the usability of the bearing device. The bearing device design can be compact having small dimensions, so that it can be used even in small spaces.